1. Technical Field
Embodiments of the subject matter disclosed herein relate to rechargeable batteries and methods of recharging rechargeable batteries.
2. Dicussion of Art
In some situations, how a rechargeable battery is charged and discharged may result in undesired battery performance and premature deterioration of the electrochemical cells of the battery. For example, repeated over or under charging of a rechargeable battery may damage its electrochemical cells. Over charging batteries has also lead to battery failures. In prior systems, a battery has been recharged by applying a voltage to the battery and charging until the battery ceases to draw current from the charging source. Such systems have been susceptible to changes in the charge voltage that have led to over and under charging and reduced performance. In other systems, the total charge in the battery is monitored by integrating current to and from the battery. However such systems have required precise current measurement that substantially increases the cost of a rechargeable battery system. Moreover, the magnitude of errors in the monitored charge of the battery tends to increase over time through successive charge and discharge cycles resulting in reduced battery performance. Other systems have relied upon a correlation between a battery's open circuit voltage and state of charge to assess the total energy stored within the battery. However for some batteries, the open circuit voltage does not correlate well to the total energy stored. These prior systems have not provided a consistent indication of the useful power contained in the battery, which has adversely affected the efficiency of the charge and discharge operations.
It may therefore be desirable to have a rechargeable battery and/or a method for a rechargeable battery that differ from those that are currently available.